Post
by slicedbread » Tue Sep 30, 2008 4:23 pm
condensed from previous lost post:
okay, according to some french guy any periodic waveform can be described by the sum of several sines of different amplitudes. this tool gives you 24 harmonics to mold together to come up with a custom shape (the ams spec actually gives you a lot more). typically, you'd want a strong (loud) fundamental (harmonic 1). that's a pure sine wave. by adding or subtracting higher order harmonics you can impart differrent timbres on your instrument. move a slider up for a sine addition, down for a cosine addition. in theory you can get very close approximations to square, saw, traingle, ramp and everything in between by tweaking individual oscillators.
there's 2 parts of ams foundry. the top part lets you shape and tune a custom oscillator waveform. the bottom lets you export a series of these oscillators auto offsetting the tuning and auto-incrementing the keymapping. < this was the tedious part i was trying to get rid of. you could always make these files in notepad but it sucked and you had no idea what the shape looked like. a side product of having complete control of each oscillator and keymapping is that you're no longer constricted to the western scale inter-note relationship of Freq = LowestNote * (2 ^ ((Note) / 12))
you can use equal tempered notes, pythagorean harmonies (perfectly integer divisible freqs... all the rage up till the middle ages), or whatever you want.
even if you just want a traditionally tuned instrument, you'd be better off by exporting a sequence and mapping each one. an ams will sound the best at the freq it was created for. if you drop an ams on simpler and let it auto-map all over the keyboard, it sounds weirder the further you get from the defined ams point. i think it has to do with aliasing and key drift... what happens when you loop 1 oscillator faster and faster. < (that may be b.s. call me out if you know better)
i think of live as one giant semi-modular synth and having your own custom waveshapes increases it's worth. most synths lock you into their pre-defined shapes.
re: multi-oscillator instruments.... hmmm.. that's an interesting idea. what you could do is export a sequence, then open each one up indivually, tweak a harmonic and save over intself. having a separate offset factor that can be applied to individual harmonics is something i may add. right now the only thing being auto-incremented in the export sequence is freq(or basenote) and keymapping.
